#include <iostream>
using namespace std;

int multiplication(int x) {
	int mul = 1;
	while(x != 0) {
		mul *= x % 10;
		x /= 10;
	}
	return mul;
}
int main() {
  int n;
  cin >> n;
  int maxmul = multiplication(n);  
  int copy = n;
  int i = 10;
  while(n != 0) {
	  int temporary_number = (copy / (i / 10)) % 10;
	  int left = copy / i;
	  int right = copy % (i / 10);
	  if(temporary_number != 9) {
	    temporary_number = 9;
	    copy = ((left - 1) * 10 + temporary_number) * (i / 10) + right;
	  }
	  n /= 10;
	  i *= 10;
	  int mul = multiplication(copy);
	  if(maxmul < mul) maxmul = mul;
	}  
	cout << maxmul; 
}